This invention relates to a bag forming and filling machine. More particularly, this invention relates to a bag forming and filling machine for loose fill material.
Heretofore, various types of machines have been employed for filling loose fill material into bags suitable for shipping purposes. For example, U.S. Pat. No. 6,035,606 describes a filling machine in which a bag is suspended within an opening of a conveyor. As the conveyor moves the bag past various stations, air is blown into the bag to open the bag, a flow of loose fill material is delivered into the bag and then the bag is closed at the upper end while still suspended from the conveyor. Filling and bagging machines of this type require manual placement of a bag onto the conveyor. However, this can be time-consuming.
Accordingly, it is an object of the invention to provide an automatic bagging machine for forming and filling bags with loose fill material,
It is another object of the invention to reduce the time required to fill and seal a series of bags with loose fill material.
It is another object of the invention to eliminate the need for a pre-made bag and to thereby reduce the cost of filled bags of loose fill material.
Briefly, the invention provides a bag forming and filling machine which is completely automatic.
The machine includes a chute for conveying a flow of loose fill material, for example, that is delivered from a hopper. Suitable means are also provided within the hopper or chute in order to deliver the flow of loose fill material on an intermittent basis such that each charge of material is predetermined for the size of the bag to be filled.
The filling machine also includes a forming means for enveloping a sheet of plastic film about the chute with overlapping longitudinally disposed edges. The forming means cooperates with any suitable supply means for supplying the sheet of plastic film, for example, from a roll.
The machine also includes a heat-sealing means for heat-sealing the overlapping edges of the plastic sheet together to form a tube about the chute. This heat-sealing means may be in the form of a heated roller that is mounted on a stationary axis to heat-seal the overlapping edges of the plastic sheet together as the sheet passes by the roller.
The machine also has a conveying means for moving the formed tube longitudinally relative to and away from the chute to continuously pull the sheet into the forming means to form a continuous tube and to allow a flow of loose fill material from the chute to fill the tube. This conveying means may employ a pair of endless belt conveyors, each of which is disposed to engage the formed tube between the conveyor and the chute.
The machine also has a heat seal bar assembly downstream of the chute relative to a flow of loose fill material for forming a transverse heat seal across the tube as well as a means for severing the tube at the transverse heat seal to form a sealed bag of loose fill material on one side and a bottom for a subsequently formed bag of loose fill material on the opposite side. For example, a hot wire or knife may be used for severing the tube.
The machine also has a means for spreading the tube into a flattened shape upstream of the heat seal bar assembly and for accumulation of the tube thereon. This means includes a pair of movable fingers or flaps that extend from the chute and means for selectively moving each of the fingers relative to the chute between a retracted position within the plane of the tube and an extended position for spreading the tube into a flattened shape. This latter means may be internally mounted to move the fingers or flaps from within the plane of the chute or externally mounted to move the fingers or flaps from outside the chute.
During operation, the conveying means moves the formed tube continuously while the heat-seal bar assembly operates on an intermittent basis. However, the movement of the tube is impeded by the extended fingers or flaps so that the tube does not move beyond the fingers or flaps but instead is spread into a flattened shape and accumulated or bunched up on the fingers or flaps. Thus, while the heat-seal bar assembly is forming a transverse seal in a part of the tube that is stationary, the tube upstream of the heat-seal bar assembly buckles and gathers itself on the extended fingers.
After a seal has been formed and the heat-seal bar assembly moved away from the tube, the fingers are retracted and a charge of loose fill material is delivered via the chute into the tube. The weight of this material then causes the bag to slide off the retracted fingers or flaps and extend under gravity away from the chute and into a smooth round shape.
After a full charge of material has been delivered into the tube, the fingers or flaps are again extended to flatten the top of the bag and the heat-seal bar assembly is again activated to seal the top of the bag. The sealed bag is also severed from the remainder of the tube and falls under gravity, for example, onto a conveyor located below the heat-seal bar assembly. The cycle of operation is then repeated.
In one embodiment, the chute is vertically disposed. In this case, a sealed bag may be deposited under gravity directly onto a conveyor located below the chute.
In another embodiment, the chute is angularly disposed to a vertical plane. In this embodiment, a ramp is located below the heat-sealing means for guiding the sealed bag of loose fill material thereon onto a conveyor located below the ramp.